The aggressive action taken by some businesses against those who post negative reviews online about their product or service is having a chilling effect on some reviewers who fear being sued, observers say.

“It’s a tremendous issue. We’re running into that all over. It’s cheap to threaten and expensive to defend,” said Paul Alan Levy, a lawyer who specializes in free speech issues related to the internet for the Washington, D.C.-based Public Citizen Litigation Group.

“So yes, many people become very quiet when they’re faced with the realistic possibility that they’re going to have to defend against a libel claim even if what they said is true. Because it’s all very well to defend, but if it costs $10,000 to defend a true comment, well you’re out $10,000. How much is it worth?”